Cutting tool assembly

ABSTRACT

A cutting tool assembly comprising a cutter body which mounts at each of its opposite sides on one end and at the proper cutting angles a relatively narrow rectangular shaped cutter blade and a triangular shaped cutter blade. These cutter blades are maintained in an operative position in engagement with each other by a clamping element that is releasably joined to the cutter body at an angle that is related to the cutter cutting angles. Support and locking provisions further facilitate maintaining this operative position. Between these cutter blades a holder for another cutter blade is supported on the cutter body. This latter cutter blade and the triangular shaped blades are aligned along with the rectangular shaped cutter blades so as to machine a plural surface profile on a work piece.

T United States Patent [191 [75] Inventor: Patrick J. Gleason, Lum,Mich. [73] Assignee: Lumco Manufacturing Company,

Lum, Mich. I

[22] Filed: Aug. 14, 1972 [21] Appl. No.:' 280,600

[52] US. Cl. 29/97, 82/36 R [51] Int. Cl B26d 1/00 [58] Field of Search29/97; 82/36 [56]- References Cited UNITED STATES PATENTS 3,136,0316/1964 Cassidy 29/97 3,180,006 4/1965 -'Emmons...; 29/97 FOREIGN PATENTSOR APPLICATIONS 1,174,100 12/1969 Great Britain 82/36 R [111 3,760,475Gleason Sept. 25, 1973 CUTTING TOOL ASSEMBLY Primary Examiner-LeonidasVlachos Attorney-Hugh L. Fisher [5 7] ABSTRACT A cutting tool assemblycomprising a cutter body which mounts at each of its opposite sides onone end and at the proper cutting angles a relatively narrow rectangularshaped cutter blade and a triangular shaped cutter blade. These cutterblades are maintained in an operative position in engagement with eachother by a clamping element that 'is releasably joined to the cutterbody at an angle that is related to the cutter cutting angles. Supportand locking provisions further facilitate maintaining this operativeposition. Between these cutter blades a holder for another cutter bladeis supported on the cutter body. This latter cutter blade and thetriangular shaped blades are aligned along with the rectangular shapedcutter blades so as to machine a plural surface profile on a work piece.

10 Claims, 4 Drawing Figures 6'8 22 fi z; ,50

' 97 f (D 62 [26 3 4 I 17 w I 12/; I Lli 53 CUTTING TOOL ASSEMBLY Thisinvention relates to an improved cutting tool assembly.

The machining of certain types of work pieces with a profile thatrequires compound surfaces be turned; e.g., the crank-pins of a vehicleengine crankshaft, presents several considerations including tool life,accuracy, the time required and the cost of the equipment. With thecrankpin as an example, to achieve accuracy with the acceptable toollife, a two step machining operation is required; i.e., a roughmachining step followed bya finish machining step. Therefore bothadditional equipment and time are needed to meet present mass productionrequirements. One of the reasons for this two step operation is the lackof an acceptable cutting tool. Single cutter blades with severaldifferent cutting edges have not been acceptable because if one cuttingedge is damaged, the entire cutting blade has to be replaced or anexpensive regrinding process is required. I

With the foregoing in mind, a new and different cutting tool assembly iscontemplated that enables compound surfaces to be formed accurately on awork piece by a single step operation.

Further contemplated is a cutting tool assembly that is durable, easilyserviced and that can accurately and efficiently form plural surfaces ona work piece with a plurality of cutter blades.

Also contemplated is a cutting tool assembly that utilizes a pluralityof cutter blades uniquely mounted so as to provide desired cuttingangles and also the proper overlap to accurately turn compound diameterand shoulder surfaces on a work piece.

1 Other objects include the provision of a-cutting tool assembly that ina novel way maintains a plurality of cutter blades in place on a cutterbody so as to achieve enhanced tool life, accuracy and operationalefficiency and that can be used by present mass production equipmenttomachine plural surface profiles.

The foregoing and other objects and advantages of the invention willbecome apparent from the following description and from the accompanyingdrawings, in which:

FIG. 1 is a side elevational view of a cutting tool assemblyincorporating the principles of the invention;

FIG. 2 is a top elevational view, looking in the direction of arrows 2-2in FIG. 1, of the cutting tool assembly shown positioned for machining avehicle crankshaft;

FIG. 3 is afront elevational view of the cutting tool assembly lookingin the direction of arrows 3-3 in FIG. 1; and

, FIG. 4 is a fragmentary enlarged view with-parts removed of a portionof the cutting tool assembly as viewed in FIG. 2.

Referring first to FIG. 1, the numeral denotes generally a cutting toolassembly that is adapted for positioning relative to a rotatable workpiece,such as a crankshaft 12. The cutting tool assembly 10 isadjustably mounted upon a block 14, which in a well known way can movethe cutting tool assembly 10 into and out of the cutting relationshipwith the crankshaft 12.

For example, the block 14 may be a part of a conventional feed mechanism(not shown) for some kind of a production line transfer machine or alathe. For purposes of demonstration and without limitation, thecrankshaft 12 is in the form of a forging and has, as

2 seen in FIG. 2, a crankpin portion 16 which when unmachined, has theshape shown by the dashed line at 17. When machined by the cutting toolassembly 10, the crankpin portion 16 will have the depicted profileincluding a crankpin surface 18 and a shoulder clearance surface 20,each being machined to a different dimension and in one step as willbecome apparent.

The cutting tool assembly 10 has a cutter body 22 with a bottom V-shapedmounting surface 24, which is seated on the block 14, and a top surface26. The body 22 also has at its cutting end 28 a cutter blade mountingprovision in the form of a pair of substantially V-shaped slots 30.

Each of the V-shaped slots 30 has a seating surface 32, which isinclined forwardly at an angle 33, as viewed in FIG. 1, and outwardly atan angle 34, as seen -in FIG. 3. Each V-shaped slot 30 also hasextending transversely from the seating surface 32 as depicted in FIG.4, an inside locating surface 35, an outside locating surface 36, and arear surface 38. In this embodiment each of these surfaces are eitherperpendicular to the seating surface 32 or tapered towards the seatingsurface to facilitate cutter blade retention.

Positioned in each of the slots 30 is a rectangular shaped side cutterblade 40 formed of a suitably hard machining metal, such as tungstencarbide, and prefer ably made to extremely close tolerances. With eachblade 40 substantially identical in shape and dimension, they can bediscarded when damaged and replaced with a new blade. Each of the cutterblades 40 has opposite parallel sides 42 and 44 and rounded cuttingedges 46. These edges 46 can have other than the depicted roundedcontour. The side cutter blades 40 when in place in the slots 30 engagethe outside locating surface 36 and the rear surface 38, which has acontour at 48 that conforms to the rounded cutting edges 46, but canhave other shapes. When in the operative position, the side cuttingblades 40 each extend beyond the side of the cutter body 22, as viewedin FIGS. 2 and 4.

Also for mounting purposes, a cutter blade support provision is includedin each slot 30 in the form of a cutter blade support member 50 that hasthe depicted triangular configuration. When the support members 50 arein position each engages the parallel side 44 of the associated sidecutter blade 40 and also the inside locating surface 34 of the slot 30.Thus, the support members 50 function somewhat as a wedge formaintaining the side cutter blades 40 in their operative positions. Thecutter blade support members 50 each have a through center opening 52for purposes to be explained. t t

' A locking provision is provided for maintaining each of the cutterblade support members 50 in place. This provision includes, asillustrated in FIG. 3, a dowel pin 56 or the like that is received in ablind hole 58 in the cutter body 22 and extends from the hole 58upwardly and into the center opening 52 in the associated cutter bladesupport member 50. The dowel pin 56 has a relatively loose fit in thehole 58 but a relatively good sliding fit in the support member opening52. To complete the locking provision, set screws 60 are threadedlycarried by the cutter body 22 at point near the lower end of each of thedowel pins 56 and when tightened force the dowel pin 56 rearwardly and,accordingly, each of the cutter blade support members 50 so as to form awedged relationship with the slots 30 and the side cutter blades 40.

Positioned on each of the cutter blade supporting members 50 is anindexable front cutter blade 62 of a relatively thin triangular shape.The front cutter blades 62 are of the throw-away type being also formedof hard cutting material, such as tungsten carbide, and manufactured toextremely close tolerances. The front cutter blades 62 have a centeropening 64 and relatively straight cutting edges 66 and end cuttingedges 68 on all sides. When in the depicted FIG. 3 operative positioneach of the front cutter blades 62 engages the side 44 of the sidecutter blade 40 and the inside locating surface 34 of the slot 30 hasthe proper radial alignment with the crankshaft 12.

If preferred the cutter blade support members 50 can be the same as thefront cutter blades 62 and thus, would provide an auxiliary cutter bladein event replacement of one of the front blades 62 was required becauseof damage. It is also possible to use a damaged front cutter blade 62 inplace of the support member 50.

For holding the front cutter blades 62 in the operative position withinthe slots 30, clamp elements 72 are provided. Each of these clampelements 72, as best observed in FIG. 1, has a cutter blade engagingsurface 74 with a depending pin 76 (FIG. 3), and rear inclined surface78 and an intermediate relieved portion 80. The depending pin 76 of eachclamp element 72 fits within the center opening 64 in a respective oneof the front cutter blades 62, whereas the rear inclined surface 78engages one of a pair of inclined or tapered surfaces 82 on the cutterbody 22. Each of the cutter body inclined surfaces 82 is formed with acompound angle that has the same angle of inclination outwardly as theseating surface angle 34 (see FIG. 3) and an angle of forwardinclination, as shown at 84 in FIG. 1. The angle 84 has a total angularextent equal to the sum of a predetermined angular amount and theforward inclination of the seating surface angle 33. Each of the clampelement inclined surfaces 78 has a complimentary inclination so as tohave a substantial area thereof in engagement with the inclined surface82 on the cutter body 22. Also, the clamp element cutter blade engagingsurfaces 74 have a relatively large area thereof in engagement with theface of the respective one of the front cutter blades 62 to facilitatemaintenence of the blades 62 in the operative position. The FIG. 1clamping position for each clamp element 72 is maintained by a suitableholding screw 86 which extends through an elongated opening 88 (FIG. 2)in the clamp element 72 and threadedly engages the cutter body 22. Theholding screw 86 is threaded into the cutter body 22 at an angle withthe same outward inclination as the seating surfaces 32 have in FIG. 3at the angle 34.

Referring again to FIG. 1, the angle 84 of the inclined surface 82 isselected so that when the holding screw 86 is tightened, the resolutionsof forces will be such that the cutter blade 62 is forced rearwardly andin the plane of the seating surface 32, thus facilitating the wedgingrelationship for holding both the front cutter blade 62 and the sidecutter blade 40 in their operative positions. If the angle 84 of thisinclined surface 82 is too steep; for example, perpendicular to the topsurface 26 of the cutter body 22, the clamp element 72, when forced intothe clamping position by the tightening of the holding screw 86 wouldtend to raise the cutter blade 62 from its viewed position in FIG. 1.Contrariwise, if the angle 84 of the inclined surface 82 is not steepenough, there will not be an adequate force imposed upon the cutterblade 62 to maintain it in its operative position. By way of example andwithout limitation, it has been determined that if the inclination ofthe seating surface angle 33 is 5", then the angle at 84 should be 30plus the 5 or 35.

Completing the assembly is a holder 90 which is slidably positioned onthe top surface 26 of the cutter body 22. The holder 90 has extendingthe length thereof a depending center portion 92 (FIG. 3), which engagesa complimentary slot 94 in the top surface 26 of the cutter body 22 soas to provide sliding adjusting movement only in the direction towardsand away from the work piece. This sliding adjusting movement can bemade by a differential screw 95, which threadedly engages both theholder 90 and a bracket 96 suitably attached to the cutter body 22. Theholder 90 is releasably maintained on the cutter body 22 by one or morescrews 97, which threadedly engage the cutter body 22. The holder 90 andthe cutter body 22 are both releasably fixed on the block 14 by a pairof elongated screws 98 that threadedly engage the block 14.

As viewed in FIG. 2, the holder 90 has a narrow front portion 100 thatextends between the two clamp elements 72. This narrow portion 100 hasan upper inclined surface 102 and at the end thereof a cutter bladereceiving slot 104 which can also be triangular shaped. This slot 104has a seating surface 106 (FIG. 1) on which is mounted a triangularshaped middle cutter blade 108 including a center opening 110. The blade108 can be of the indexable throw-away type and thus similar to thefront cutter blades 62 and is appropriately inclined by the seatingsurface 106 so that the proper cutting angles are provided and also soas to be in the required approximate radial alignment with the center ofthe crankpin portion 16.

For holding the middle cutter blade 108 in the operative position, aclamp element 112 is employed that is similar structurally andfunctionally to the clamp ele ments 72. This clamp element 112 has acutter blade engaging surface 114 provided with a depending pin 116 anda rear inclined surface 118. When in the FIG. 1 clamping position, thedepending pin 116 engages the center opening in the middle cutter blade108, the surface 114 is flush against the face of the blade 108, and therear inclined surface 1 18 engages a top portion 120 of the holder 90.As with the clamp elements 72, the angular relationship is such as toprovide the proper restraining forces for urging the middle cutter blade108 rearwardly in the plane of its seating surface 106. A suitable screw122 holds the clamp element 112 in the depicted position.

As viewed in FIGS. 1 and 2, the alignment of the front cutter blades 62and the middle cutter blades 108 respectively on the cutter body 22 andthe holder 90 takes into consideration the different plane location ofthe middle cutter blade 108 and is such that an uninterrupteddiametrical cut is made on the crankpin surface 18. Also, the bladesizes are selected to provide the FIG. 2 illustrated crankpin profile.As the cutting tool assembly 10 is fed into the crankpin portion 16, itwill be noted that the side cutter blades 40 and the front cutter blades62 have substantially more metal to remove than the middle cutter blade108. This the described cutting tool assembly 10 can accomplish accu- 1rately in one step and without sacrificing durability.

Also, it will be noted that the end cutting edges 68 of the front cutterblades 62 provide the crankpin surface 18 with the proper size fillet at124 and that the side cutter blades 40 provide the shoulder clearancesurfaces 20, which terminate in a larger diameter at a fillet 126. Thissurface 20 and fillet 126 provide somewhat of a boss for facilitatingthe installation and positioning of the vehicle crank in the crankpinportion 16.

The single machining step is done with indexable throwaway cutter bladesthat can be replaced in a minimum amount of time without concern aboutrealignment. Furthermore, when the support members 50 are the same asthe cutter blades 62 they can serve as auxiliary blades and be used toreplace one of the damaged front cutter blades 62. The resolution of theforces with respect to the clamp elements 72 and the clamp element 112provide optimim holding forces that maintain the wedge like relationshipso that the cutting blades 62 and 40 cannot shift or move so as to bedamaged or damage the crankshaft 12 during the machining operation.

What is claimed is:

*1. A cutting tool assembly comprising a cutter body including amounting surface and a cutting end having cutter blade mounting means onopposite sides thereof, each mounting means including a slot openingoutwardly from the cutting end and being so arranged as to have acertain angular relationship with the mounting surface for establishingdesired cutting angles; the cutter body also-including a pair ofinclined surfaces each displaced from a respective one of the pair ofslots and being provided with an inclination having a predeterminedrelationship with the certain angular relationship of each of the pairof slots; a pair of side cutter blades respectively positioned withinthe slots so that in the operative position thereof the cuttingedgesthereof project from the side of the cutter body; a pair of front cutterblades respectively positioned within the slots so that in the operativeposition thereof each front cutter blade is in a certain cuttingalignment relative to the other and a respectiveone of the side cutterblades and is also arranged so as to be in engagement with a respectiveone of the pair of side cutter blades; and a pair of clamp elements.respectively adjustably positioned on the cutter body adjacent the pairof front cutter blades so as to have a predetermined angularrelationship with a respective one of the pairs of slots, each clampelement in the clamping position thereof having an inclined surface inengagement with a respective one of the pair of inclined surfaces on thecutter body and a cutter blade engaging portion in engagement with arespective one of the pair of front cutter blades so as to maintain arespective one of the pair of front cutter blades and a respective oneof the pair of side cutter blades in the operative positions thereof forcutting a certain profile.

2. A cutting tool assembly as described in claim 1, further including aholder removably positioned on the cutter body and having a cutter blademounted thereon so as to be in the operative position thereof and incutting alignment with each of the pair of front cutter blades.

3. A cutting tool assembly as described in claim 2, further including aclamp element releasably positioned on the holder and having a frontportion engagable with the holder mounted cutter clade and a rearportion provided with an inclined surface engagable with the holder at acertain angle so as to maintain the holder mounted cutter blade in theoperative position thereof.

4. A cutting tool assembly as described in claim 1, wherein each of thepair of slots are defined by a seating surface having a certain angularrelationship with the mounting surface for establishing the desiredcutting angles and inside and outside locating surfaces extendinglaterally from the seating surface and at a predetermined angle relativethereto, each of the pair of side cutter blades is positioned within arespective one of the pair of slots and in engagement with both theseating surface and the outside surface and each of the pair of forwardcutter blades is positioned within a respective one of the slots so asto be in engagement with both the inside locating surface and arespective one of the pair of the side cutter blades.

5. A cutting tool assembly as described in claim 4, wherein the mountingmeans further includes a pair of support members respectively positionedwithin the pair of slots and in engagement with the seating surface anda respective one ofthe pair of front cutter blades and a respective oneof the pair of side cutter blades.

6. A cutting tool assembly as described in claim 4, wherein the slotsare each triangular shaped and each of the pair of front cutter bladesare indexable and also triangular shaped and have a central openingtherein engagable with the cutter blade engaging portion of a respectiveone of the pair of clamp elements.

'7. A cutting tool assembly as described in claim 1, wherein themounting means includes a pair of auxiliary cutter blades respectivelypositioned within a respective one of the pair of slots on the seatingsurface thereof and in the operative position thereof in engagement bothwith'a respective one of the pair of side cutter blades and the outsidelocating surface, each auxiliary cutter blade having a triangular shapeand having a central opening therein; the mounting means also in-.cluding means locking each of the pair of auxiliary cutter blades inthe operative position thereof; each of the pair of slots beingtriangular shaped and defined by a seating surface having a certainangular relationship with the cutter body mounting surface forestablishing desired cutting angles and inside and outside locatingsurfaces each extending laterally from the seating surface and at apredetermined angle relative thereto; each of the pair of front cutterblades being indexable and interchangeable with the auxiliary cutterblades, each of the pair of front cutter blades also triangular shapedand having a central opening therein engagable with the cutter bladeengaging portion of a respective one of the pair of the clamp elements.

8. A cutting tool assembly as described in claim 7, wherein the lockingmeans includes a pair of pin elements extendable from the cutter bodyand into the central opening in a respective one of the pair ofauxiliary cutter blades and screw means carried by the cutter body forlocking each pin element into the locking position and accordingly arespective one of the pair of auxiliary cutter blades in the operativeposition thereof.

9. A cutting tool assembly as described in claim 8, further including aholder removably positioned in the cutter body and having a cutter blademounted thereon so as to be in the operative position thereof and incutting alignment with each of the pair of front cutter blades and aclamp element releasably positioned on the holder and having a frontportion engagable with the holder mounted cutter blade and a rearportion provided with an inclined surface engagable with the holder at acertain angle so as to maintain the holder mounted cutter blade in theoperative position thereof.

10. A cutting tool assembly comprising a cutter body having a mountingsurface, a cutting end and a pair of spaced apart triangular shapedslots opening outwardly from the cutting end, each of the pair of slotsbeing defined by a seating surface having a certain forward inclinationand a certain lateral inclination both relative to the mounting surfacefor establishing desired cutting angles and inside and outside locatingsurfaces perpendicular with and extending from the seating surface; thecutter body also including a pair of inclined surfaces each displacedfrom a respective one of the pair of slots and being provided with aninclination having a certain relationship to the inclinations of theseating surface; a pair of rectangular shaped side cutter bladesrespectively positioned within the slots and in engagement with both theseating surface and the outside surface of a respective one of the pairof slots so that in the operative position thereof the cutting edgesthereof project from the side of the cutter body; a pair of triangularshaped auxiliary cutter blades respectively positioned within the pairof slots, each of the pair of auxiliary cutter blades having a centralopening and being positioned on the seating surface of a respective oneof the pair of slots and in engagement with both a respective one of thepair os side cutter blades and the respective inside locating surface; apair of triangular shaped front cutter blades respectively positionedwithin the slots and having a central opening, each of the pair of frontcutter blades being positioned on a respective one of the pair ofauxiliary cutter blades and in engagement with both the inside locatingsurface of a respective one of the pair of slots and a respective one ofthe pair of side cutter blades and aligned in the operative positionthereof so that the cutting edges thereof are in cutting alignment witheach other; the pair of auxiliary cutter blades and the pair of frontcutter blades being interchangeable with each other; a pair of clampelements respectively adjustably positioned on the cutter body adjacentthe pair of front cutter blades so as to have an inclination relative tothe cutter body mounting surface corresponding to the certain lateralinclination of the seating surfaces of the pair of slots, each clampelement in the clamping position thereof having an inclined surfaceengageable with a respective one of the pair of inclined surfaces on thecutter body and a cutter blade engaging portion in engagement with arespective one of the pair of front cutter blades and also in engagementwith the central opening in a respective one of the pair of front cutterblades so as to maintain a respective one of the front cutter blades anda respective one of the side cutter blades in the operative positionthereof; locking means for each of the pair of auxiliary cutter blades;the locking means including a pair of pin elements carried by the cutterbody and respectively extending into the central opening in the pair ofauxiliary cutter blades and screw means for locking the pair of pinelements in place so as to maintain a respective one of the auxiliaryblade cutters and a respective one of the side cutter blades in theoperative positions thereof; and a holder adjustably positioned on thecutter body and having an end portion thereof extending between the pairof front cutter blades, the end portions having a middle cutter blademounted thereon so as to be in the operation position thereof and incutting alignment with each of the pair of front cutter blades at apredetermined cutting angle so as to cooperate with the pair of sidecutter blades for developing a machining profile including an elongateddiameter portion and a shoulder portion laterally extending from thediameter portion, and a clamp element releasably positioned on theholder and having a front portion engageable with the holder mountedcutter blade and a rear portion provided with an inclined surfaceengageable with the holder at a certain angle so as to maintain theholder mounted blade in the operative position thereof.

1. A cutting tool assembly comprising a cutter body including a mountingsurface and a cutting end having cutter blade mounting means on oppositesides thereof, each mounting means including a slot opening outwardlyfrom the cutting end and being so arranged as to have a certain angularrelationship with the mounting surface for establishing desired cuttingangles; the cutter body also including a pair of inclined surfaces eachdisplaced from a respective one of the pair of slots and being providedwith an inclination having a predetermined relationship with the certainangular relationship of each of the pair of slots; a pair of side cutterblades respectively positioned within the slots so that in the operativeposition thereof the cutting edges thereof project from the side of thecutter body; a pair of front cutter blades respectively positionedwithin the slots so that in the operative position thereof each frontcutter blade is in a certain cutting alignment relative to the other anda respective one of the side cutter blades and is also arranged so as tobe in engagement with a respective one of the pair of side cutterblades; and a pair of clamp elements respectively adjustably positionedon the cutter body adjacent the pair of front cutter blades so as tohave a predetermined angular relationship with a respective one of thepairs of slots, each clamp element in the clamping position thereofhaving an inclined surface in engagement with a respective one of thepair of inclined surfaces on the cutter body and a cutter blade engagingportion in engagement with a respective one of the pair of front cutterblades so as to maintain a respective one of the pair of front cutterblades and a respective one of the pair of side cutter blades in theoperative positions thereof for cutting a certain profile.
 2. A cuttingtool assembly as described in claim 1, further including a holderremovably positioned on the cutter body and having a cutter blademounted thereon so as to be in the operative position thereof and incutting alignment with each of the pair of front cutter blades.
 3. Acutting tool assembly as described in claim 2, further including a clampelement releasably positioned on the holder and having a front portionengagable with the holder mounted cutter clade and a rear portionprovided with an inclined surface engagable with the holder at a certainangle so as to maintain the holder mounted cutter blade in the operativeposition thereof.
 4. A cutting tool assembly as described in claim 1,wherein each of the pair of slots are defined by a seating surfacehaving a certain angular relationship with the mounting surface forestablishing the desired cutting angles and inside and outside locatingsurfaces extending laterally from the seating surface and at apredetermined angle relative thereto, each of the pair of side cutterblades is positioned within a respective one of the pair of slots and inengagement with both the seating surface and the outside surface andeach of the pair of forward cutter blades is positioned within arespective one of the slots so as to be in engagement with both theinside locating surface and a respective one of the pair of the sidecutter blades.
 5. A cutting tool assembly as described in claim 4,wherein the mounting means further includes a pair of support membersrespectively positioned within the pair of slots and in engagement withthe seating surface and a respective one of the pair of front cutterblades and a respective one of the pair of side cutter blades.
 6. Acutting tool assembly as described in claim 4, wherein the slots areeach triangular shaped and each of the pair of front cutter blades areindexable and also triangular shaped and have a central opening thereinengagable with the cutter blade engaging portion of a respective one ofthe pair of clamp elemenTs.
 7. A cutting tool assembly as described inclaim 1, wherein the mounting means includes a pair of auxiliary cutterblades respectively positioned within a respective one of the pair ofslots on the seating surface thereof and in the operative positionthereof in engagement both with a respective one of the pair of sidecutter blades and the outside locating surface, each auxiliary cutterblade having a triangular shape and having a central opening therein;the mounting means also including means locking each of the pair ofauxiliary cutter blades in the operative position thereof; each of thepair of slots being triangular shaped and defined by a seating surfacehaving a certain angular relationship with the cutter body mountingsurface for establishing desired cutting angles and inside and outsidelocating surfaces each extending laterally from the seating surface andat a predetermined angle relative thereto; each of the pair of frontcutter blades being indexable and interchangeable with the auxiliarycutter blades, each of the pair of front cutter blades also triangularshaped and having a central opening therein engagable with the cutterblade engaging portion of a respective one of the pair of the clampelements.
 8. A cutting tool assembly as described in claim 7, whereinthe locking means includes a pair of pin elements extendable from thecutter body and into the central opening in a respective one of the pairof auxiliary cutter blades and screw means carried by the cutter bodyfor locking each pin element into the locking position and accordingly arespective one of the pair of auxiliary cutter blades in the operativeposition thereof.
 9. A cutting tool assembly as described in claim 8,further including a holder removably positioned in the cutter body andhaving a cutter blade mounted thereon so as to be in the operativeposition thereof and in cutting alignment with each of the pair of frontcutter blades and a clamp element releasably positioned on the holderand having a front portion engagable with the holder mounted cutterblade and a rear portion provided with an inclined surface engagablewith the holder at a certain angle so as to maintain the holder mountedcutter blade in the operative position thereof.
 10. A cutting toolassembly comprising a cutter body having a mounting surface, a cuttingend and a pair of spaced apart triangular shaped slots opening outwardlyfrom the cutting end, each of the pair of slots being defined by aseating surface having a certain forward inclination and a certainlateral inclination both relative to the mounting surface forestablishing desired cutting angles and inside and outside locatingsurfaces perpendicular with and extending from the seating surface; thecutter body also including a pair of inclined surfaces each displacedfrom a respective one of the pair of slots and being provided with aninclination having a certain relationship to the inclinations of theseating surface; a pair of rectangular shaped side cutter bladesrespectively positioned within the slots and in engagement with both theseating surface and the outside surface of a respective one of the pairof slots so that in the operative position thereof the cutting edgesthereof project from the side of the cutter body; a pair of triangularshaped auxiliary cutter blades respectively positioned within the pairof slots, each of the pair of auxiliary cutter blades having a centralopening and being positioned on the seating surface of a respective oneof the pair of slots and in engagement with both a respective one of thepair os side cutter blades and the respective inside locating surface; apair of triangular shaped front cutter blades respectively positionedwithin the slots and having a central opening, each of the pair of frontcutter blades being positioned on a respective one of the pair ofauxiliary cutter blades and in engagement with both the inside locatingsurface of a respective one of the pair of slots and a respective one ofthe Pair of side cutter blades and aligned in the operative positionthereof so that the cutting edges thereof are in cutting alignment witheach other; the pair of auxiliary cutter blades and the pair of frontcutter blades being interchangeable with each other; a pair of clampelements respectively adjustably positioned on the cutter body adjacentthe pair of front cutter blades so as to have an inclination relative tothe cutter body mounting surface corresponding to the certain lateralinclination of the seating surfaces of the pair of slots, each clampelement in the clamping position thereof having an inclined surfaceengageable with a respective one of the pair of inclined surfaces on thecutter body and a cutter blade engaging portion in engagement with arespective one of the pair of front cutter blades and also in engagementwith the central opening in a respective one of the pair of front cutterblades so as to maintain a respective one of the front cutter blades anda respective one of the side cutter blades in the operative positionthereof; locking means for each of the pair of auxiliary cutter blades;the locking means including a pair of pin elements carried by the cutterbody and respectively extending into the central opening in the pair ofauxiliary cutter blades and screw means for locking the pair of pinelements in place so as to maintain a respective one of the auxiliaryblade cutters and a respective one of the side cutter blades in theoperative positions thereof; and a holder adjustably positioned on thecutter body and having an end portion thereof extending between the pairof front cutter blades, the end portions having a middle cutter blademounted thereon so as to be in the operation position thereof and incutting alignment with each of the pair of front cutter blades at apredetermined cutting angle so as to cooperate with the pair of sidecutter blades for developing a machining profile including an elongateddiameter portion and a shoulder portion laterally extending from thediameter portion, and a clamp element releasably positioned on theholder and having a front portion engageable with the holder mountedcutter blade and a rear portion provided with an inclined surfaceengageable with the holder at a certain angle so as to maintain theholder mounted blade in the operative position thereof.